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How to fix a SIP roof?

We recently have had renovations done on our home. We have a structured insulated panel (SIP) home and the roof has always seem to be the issue. The roof originally had the roofing panels directly attached to the SIPs. We change it to have furring strips and than more plywood and than roofing materials (wrap and shingles) to allow air flow. This however has created more sweating to the inside of the house. We have moisture coming down through the ease of the roof in several rooms. Does anyone know how this can be fixed or what we should do to correct this problem? Appreciate any help or insight. Thank you.

Asked by kc18
Posted Jul 2, 2018 10:04 AM ET
Edited Jul 2, 2018 11:34 AM ET


3 Answers

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First of all, can you tell us your name? (I'm Martin.)

It's hard to tell from your description what's going on. It would be helpful to know where the "sweating" (condensation) occurs, and under what weather conditions. Does it happen when the weather is cold? Hot? During the morning? At night?

There are many possibilities, but air leakage at panel seams may be an issue contributing to this problem.

Answered by Martin Holladay
Posted Jul 2, 2018 11:33 AM ET


Hi Martin,

My name is Karen. I live in PA.

The sweating has start at the very pitch of the roof (where main support is) and seems to be streaming down towards to the side walls. We have cathedral ceiling. It seems to happen during the day as the temperature gets warmer and sun beats on the roof. Never during winter.

Do you know if the roof panels can be removed without causing an issue to the structure of the house given the whole house is made of these panels? Also, do you know of anyone in Pennsylvania area that specializes in this type of construction that could look at the roof? We are near Lehigh Valley.

Answered by kc18
Posted Jul 2, 2018 12:23 PM ET


There have been several posts on our Q&A pages recently about summertime condensation near the ridge of a cathedral ceiling. I can't find all of these posts, but here are a few links to similar cases:

Why is there condensation on my cathedral ceiling?

How can I stop mold from growing on my A-frame ceiling?

Cathedral SIPs are sweating in summer

Trouble on the Roof

A site visit is necessary to determine what's going on. A few general observations:

1. Every SIP roof needs to include details (usually, both tape and spray foam) to seal all SIP seams.

2. Most SIP roof problems can be traced to air sealing problems (air leakage).

3. Condensation occurs when warm, humid air contacts a cold surface. If condensation happens during the summer, the first mystery to be solved is: What surface is cold? Candidates include air conditioning ducts and roof materials cooled by night sky radiation.

Answered by Martin Holladay
Posted Jul 2, 2018 2:22 PM ET

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